This section provides background information related to the present disclosure which is not necessarily prior art.
In general, an airbag module and a seat belt device are installed in a vehicle to protect drivers and passengers upon vehicle collision.
The airbag module is installed at a driver seat and a passenger seat of the vehicle and instantly expanded upon the vehicle collision to protect the heads and chests of the occupants.
If rear-side collision, side collision or head-on collision occurs in the vehicle running in a predetermined speed, an inflator of a passenger airbag module is exploded while generating gas pressure, so that an airbag cushion is expanded to prevent the passenger from directly colliding with internal structures of the vehicle, thereby minimizing the bodily injury.
In detail, as the rear-side collision or the head-on collision of the vehicle is detected by an impact sensor of the passenger airbag module, an explosive igniter and a gas generator installed in an inflator housing are sequentially ignited, so that high-pressure gas is generated. Thus, the airbag cushion folded in multiple steps is deployed toward the passenger while tearing an airbag cover, thereby preventing the passenger from colliding with the interior structures of the vehicle.
An example of the passenger airbag modules is disclosed in Japanese Unexamined Patent Publication No. 1995-025303 published on Jan. 27, 1995 (hereinafter, referred to as patent document 1).
FIG. 1 schematically shows the deployment state of a passenger airbag cushion disclosed in patent document 1.
As shown in FIG. 1, an airbag device according to patent document 1 includes a bag body 5 having an outer bag 7 provided therein with inflators 6 and an inner bag 8 branching from the outer bag 7 to support the external shape of the bag body 5. The inner bag 8 includes a plurality of branch sections 8 extending to a rear side of the bag body 5 along an inner surface of the bag body 5. An air hole 5a is formed in the bag body 5 to communicate with the outside.
According to the airbag device of patent document 1, the inner bag 8 formed in the bag body 5 is primarily expanded and deployed due to gas pressure generated from the inflators 6 when the airbag is deployed.
In detail, the airbag device according to patent document 1 primary expands and deploys the inner bag 8 having a volume remarkably smaller than that of the bag body 5 and then expands and deploys the bag body 5 by using air introduced through the air hole 5a, so the bag body 5 can be instantly expanded and deployed. Therefore, the airbag device according to patent document 1 can safely protect the occupants by reliably restraining the occupants.
However, the airbag device according to patent document 1 must form the inner bag 8 including the branch sections 9 in the bag body 5, so the process for manufacturing the bag body 5 and the inner bag 8 may be complicated, so that the manufacturing cost for the airbag device may be increased.